AbstractThis thesis present the work on the chemical constituents of Sarcococca and related medicinal plants.

Section-A It describes the studies on the chemical constituents of the whole plant of Sarcococca brevifolia and Sarcococca zeylanica, the work on these plants have led to the isolation of six new steroidal alkaloids, four of them were isolated from Sarcococca brevifolia (80-83) and two were yielded by Sarcococca seylanica (84-85)

Section-B It deals with the chemical investigation of Murraya paniculata the work on this plant have yielded three known coumarins but they are first time isolated from this plant (86-88)

Section-C It describes the isolation of one known fatty acid ester (89) and one known fatty acid (90) from Nigella sativa. Some portion of the fraction were also subjected to GC-MS to identify other constituents.